Metal oxide nanoparticles are useful for a variety of applications, including increasing the refractive indices of transparent organic matrices.
Various methods have been taught for the production of metal oxide nanoparticles with control of particle size and particle size distribution. For example, U.S. Pat. No. 7,169,375 (Chisolm) discloses a method of making metal oxide nanoparticle sols by hydrolyzing metal alkoxides.
U.S. Pat. Nos. 6,329,058 and 6,432,526 (Amey et al.) describe methods for making metal oxide nanoparticles from metal alkoxides via complexation and hydrolysis.
Metal oxide nanoparticles have been synthesized in a plasma reactor. U.S. Pat. No. 5,749,937 (Detering et al.) discloses a Fast Quench Reactor and Method for the conversion of titanium tetrachloride vapor to an ultrafine powder of titanium dioxide under plasma conditions.
U.S. Pat. No. 7,217,407 to Zhang purportedly describes a plasma synthesis method of increasing particle surface area and decreasing the concentration of over-sized particles in a process for making metal oxide particles.